Acetamide‐modified hyper‐cross‐linked resin: Synthesis,characterization, and adsorption performance to phenol from aqueous solution

Acetamide‐modified hyper‐cross‐linked resin, HCP‐HMTA‐AA, was prepared and its adsorption performance was evaluated using phenol as the adsorbate. The prepared HCP–HMTA–AA owned predominant micro/mesopores and medium polarity, making it possess a superior adsorption to phenol as compared with polystyrene (PS), chloromethylated polystyrene (CMPS), hyper‐cross‐linked polymer (HCP) and amino‐modified hyper‐cross‐linked resin (HCP–HMTA). The adsorption enthalpy was ?99.56 kJ/mol at zero fractional loading, multiple hydrogen bonding contributed to such a great adsorption enthalpy and an approximately planar hexahydric ring was formed between acetamide of HCP–HMTA–AA and phenol. The dynamic capacity of phenol on HCP–HMTA–AA was 291.3 mg/g at a feed concentration of 946.2 mg/L and a flow rate of 48 mL/h and the resin column was almost regenerated by a mixed solvent including 50% of ethanol (v/v) and 0.01 mol/L of sodium hydroxide (w/v). HCP–HMTA–AA was repeatedly used for five times and the equilibrium adsorption capacity for the five time reached 94.2% of the equilibrium adsorption capacity for the first time. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41597.     

CO2 Adsorption capacity of activated N‐doping porous carbons prepared from graphite nanofibers/polypyrrole

In this study, N‐doping porous carbons (NPCs) with a 3D aperiodic hierarchical and layered structure were prepared by the sodium hydride (NaOH) activation of graphite nanofibers (GNFs)/polypyrrole (PPY) composites. The effects of the N groups and structural features on the CO₂ adsorption capacity of NPCs were investigated by N₂ full isotherms, XRD, SEM, and TEM. The CO₂ adsorption capacity was measured by the CO₂ isothermal adsorption at 25°C and 1 atm. It was found that GNFs served as a substrate and layered graphitic carbons were formed by the thermal annealing of PPY. The content of N groups and textural properties of NPCs were enhanced with increasing activation temperature, resulting in improved CO₂ adsorption capacity. The CO₂ adsorption isotherms showed that GPK‐600 exhibited the best CO₂ adsorption capacity of 88.8 mg/g when the activation temperature was 600°C. The result indicates that the pore size and its distribution of NPCs lead to feasible contact CO₂, and the presence of high N groups on the NPCs could have resulted in further stabilization of the surface effect. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40517.     

Synthesis and characterization of PS‐b‐PDMS‐b‐PS triblock copolymer

A series of polystyrene‐b‐poly(dimethylsiloxane)‐b‐polystyrene (PS/PDMS/PS) triblock copolymers had been synthesized by atom transfer radical polymerization (ATRP). The products had been characterized by Fourier transform infrared, gel permeation chromatography, differential scanning calorimetry, thermogravimetric analysis, contact angle, and scanning electron microscope. The results indicate that the PS chains have been successfully blocked onto the PDMS back bone, and the PS‐b‐PDMS‐b‐PS triblock copolymers have low‐surface tension, good thermal stability, and microphase separation configuration. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Aqueous core polystyrene microspheres fabricated via suspension polymerization basing on a multiple pickering emulsion

Multi‐hollow or hollow polymer particles are of great interest in many fields. Here we successfully fabricate polystyrene microspheres with aqueous cores through w/o/w Pickering emulsion stabilized by modified SiO₂ nanoparticles. The final structure and constituents of the microspheres is investigated via SEM, X‐ray photoelectron spectra, and thermo‐gravimetric analysis. The results demonstrate that the size and amount of aqueous cores in the microspheres can be tuned by the original structure of the multiple emulsions: when the volume fraction of inner water is 0.2, the inner structure of the microspheres obtained is porous and each pore is not interconnected; when the volume fraction of inner water is increased to 0.7, the resulting products are hollow microspheres and when 0.3% wt/vol of salt is added to the inner aqueous phase, the inner pores of the resulting microspheres enlarge or even coalesce. The multi‐hollow or hollow polystyrene microspheres with aqueous cores are expected to be candidates for encapsulation in biotechnology. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39761.     

Effects of different porous fillers on interfacial properties of poly (vinyl alcohol) hybrid films

Poly(vinyl alcohol) (PVA)-based hybrids have demonstrated broad liquid separation applications but separation performances are constrained by the compatibility between fillers and polymer, and thus it is essential to study the interfacial properties of these hybrids. In this work, PVA hybrids with four different porous fillers have been fabricated and characterized with Fourier transform infrared, X-ray diffraction, Scanning electron microscope, swelling and contact angle tests. Swelling results show that PVA has a degree of swelling (DS) of 79% in water but the swelling is compressed after adding fillers and the DS for PVA hybrids has decreased by 19%, 17%, 15%, and 9% for 30 wt% loading of ZIF-8, UiO-66, Hβ and ZSM-5, respectively. For methanol and its 10 wt% aqueous solution, similar swelling results are obtained due to mutual interactions among the filler, polymer and test liquids. Based on water and glycerol contact angle results, the surface energy of PVA is estimated to be 40.56 Nm⁻¹ and it drops to 27.39 Nm⁻¹ after adding less hydrophilic ZIF-8 or rise to 48.56 Nm⁻¹ after introducing more hydrophilic ZSM-5. The high-film hydrophilicity and then large surface energy have rendered methanol/water sorption selectivity of PVA hybrids decrease to some extent or vice versa.     

In situ studies of bovine serum albumin adsorption onto functionalized polystyrene latices monitored with a quartz crystal microbalance technique

The adsorbability of bovine serum albumin (BSA) onto poly(styrene‐co‐itaconic acid) (PS–IA), poly(styrene‐co‐hydroxyethyl methacrylate) (PS–HEMA), poly(styrene‐co‐acrylic acid) (PS–AA), and poly(styrene‐co‐methacrylic acid) (PS–MAA) latices were investigated with a quartz crystal microbalance. The amount adsorbed onto the functionalized latices, except for PS–MAA, was greater than that adsorbed onto polystyrene (PS) latex. To explain this result, two kinds of interaction forces were considered, hydrogen bonding and hydrophobic interactions, whereas electrostatic interaction was assumed to be small. When comparing the two extremes of hydrophobic interaction and hydrogen bonding, the latter was stronger. The corrected adsorption mass suggested that the BSA molecules were adsorbed onto the PS–MAA latex in a side‐on mode. However, in the case of the PS, PS–IA, PS–HEMA, and PS–AA latices, the BSA molecules were probably adsorbed in multiple layers. The presence of the BSA in the latex particle surface was verified by attenuated total reflectance/Fourier transform infrared spectroscopy and atomic force microscopy. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42055.     

Improving iodine adsorption performance of porous organic polymers by rational decoration with nitrogen heterocycle

Four kinds of porous aminal-linked organic polymers (PAOPs) were synthesized via one-step condensation between cheap melamine and respective aldehydes decorated with different nitrogen heterocycle, to evaluate the influence of nitrogen heterocycle on the adsorption performance of target polymer toward iodine. Though having the smallest surface area of 209.9 m²/g, PAOP-4 decorated with pyridine group exhibits an adsorption capacity of 108 wt% (iodine/adsorbent weight%), surpassing other three PAOPs with Brunauer–Emmett–Teller area varying from 305.8 to 533.0 m²/g. Based on Raman spectral analyses, the characteristic band of I₃⁻ and I₅⁻ was used to evaluate the electronic interaction between iodine and the nitrogen heterocycle, giving an order of pyridine > tetrazole > pyrazole > imidazole. This manifests the vital role of chemical interaction playing in the iodine adsorption by PAOP-4, which is much helpful for designing high-performance organic adsorbent toward iodine.     

3D-Printed thermoplastic polyurethane/graphene composite with porous segregated structure: Toward ultralow percolation threshold and great strain sensitivity

Low-percolation threshold and large deformation capacity are two critical attributes of the strain sensor, which determine its sensitivity and stability respectively. However, endowing these two attributes to the strain sensor simultaneously is still a great challenge in this field. In this work, the strain sensor with the three-dimensional porous segregated structure constructed by graphene wrapped thermoplastic polyurethane (TPU) particles was fabricated successfully through the selective laser sintering technology. Results demonstrated that the percolation threshold of the composite is only 0.2 wt% and the strain gage factor can reach as high as 668.3, which represents the excellent sensitivity of the strain sensor. Furthermore, after 10 circles of stretching at the 15% strain, resistance-strain behavior of the strain sensor shows great repeatable, which represents the remarkable stability. Therefore, the highly sensible and stable strain sensor was fabricated successfully, which will provide the guidance for the manufacture of the high-performance strain sensor.     

High oil absorbable superhydrophobic melamine sponges and evaluation in oil spill clean-ups

Facing the environmental crisis to leakage of oil spills and chemicals, multifunctional absorbent with high oil absorption and selectivity urgently need to solve this matter. In our work, a high oil sorbent was designed and favorably fabricated by two simple immersions using melamine sponge as pristine and a series of oils were used to evaluate the oil absorption performances of the absorbent. Two immersions include adhesion of dopamine and grafting of the long chain hydrophobic agent. The prepared material is superhydrophobic with water contact angle is 165.9° ± 2.17 and high oil absorption to chloroform is 174 times by own weight, other oils are close to or over 100 times, but to water is only 0.5 times. The reusability reveals that the average recovery can keep more than 95% after 20 cycles. These advantages make it really potential to use in oil spill clean.     

Adsorption of lactic acid onto three ionic liquid‐modified porous polymers

Three ionic liquid (IL)‐modified porous polymers were synthesized and used for the adsorption of lactic acid. The experimental adsorption kinetics and equilibrium data from the IL‐modified polymers were obtained. The kinetic study revealed a low temperature to be advantageous to the adsorption process. The dependence of the level of lactic acid adsorption on the amount of polymer, initial lactic acid concentration, and pH was examined at equilibrium. The maximum efficiency was obtained using the maximum adsorbent dose. A comparison of lactic acid adsorption at different pH revealed anion exchange to be the main interaction between the lactic acid and polymers, not molecular adsorption. The amounts adsorbed were fitted to the Langmuir, Freundlich, and Temkin equations. The equilibrium data for modified polymers (imidazole modified polymer, methylimidazole modified polymer, and ethylimidazole modified polymer) were best represented by the Langmuir and Freundlich isotherm with R² values of 0.99. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Breath figure templated semifluorinated block copolymers with tunable surface properties and binding capabilities

Patterning of functionalized polymeric surfaces enables the adjustment of their characteristics and use in novel applications. We prepared breath figure (BF) films from three semifluorinated diblock copolymers, which all are composed of a polystyrene block and a semifluorinated one to compare their surface properties. “Click” chemistry was employed to one of the polymers, containing a poly(pentafluorostyrene) block to incorporate hydrophilic sugar or carboxylic acid moieties. The structure of the polymer alters the obtained porous morphology of the films. Contact angle (CA) analyses of the BF films reveals that the surface porosity increases water CAs compared with solvent cast films, and, in the case of hydrophobic polymers, leads to significant increase in the CAs of dodecane. The hydrophobicity of the BF films is further amplified by the removal of the topmost layer which leads in some cases to superhydrophobic surfaces. BF films containing glucose units are hydrophilic exhibiting water CAs below 90°. These glycosylated porous surfaces are shown to bind lectin Con A‐FITC or can be labelled with isothiocyanate marker. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41225.     

Facile preparation of a crosslinked hydrophilic UHMWPE membrane

Ultra high molecular weight polyethylene (UHMWPE) filters are widely used in water treatment. In the present work, a facile crosslinking technique is first applied to a UHMWPE flat membrane as a model to realize long-lasting hydrophilicity and improved water treatment efficiency. In the presence of a crosslinker, N, N′-methylene bisacrylamide (MBA), 2-hydroxyethyl methacrylate (HEMA), a hydrophilic modifier, is soaked into the surface of UHMWPE particles by blending. Then, a crosslinking reaction occurs during the initial sintering stage. Finally, sintering is completed at high temperature and pressure. The FTIR and SEM results show that HEMA is successfully crosslinked on the UHMWPE particle surface. Compared to a pristine membrane, the crosslinked UHMWPE flat membrane presents a lower water contact angle and is more rapidly penetrated by water. As a result, the crosslinked membrane can realize pressureless filtration. Another meaningful result is that the water flux recovery rate (FRR) is extremely high both for BSA and sludge filtration tests. Also a parameter K of 1 was obtained to represent the efficiency of the membrane treatment of water under pressureless conditions. These findings demonstrate that the crosslinking strategy is an effective method for realizing long-lasting hydrophilicity and is very promising for UHMWPE filters and other engineering applications.     

Effect of solvent quality and humidity on the porous formation and oil absorbency of SAN electrospun nanofibers

In this study, nanofibrous mat with high oil sorption capability was prepared via one‐step electrospinning process without any further post‐treatments. For this purpose, the fabrication of styrene/acrylonitrile copolymer nanofibers was carried out using various dimethylformamide (DMF)/tetrahydrofuran and DMF/ethanol (DMF/EtOH) binary mixture ratios in an electrospining atmosphere with various relative humidity (RH) levels. Scanning electron microscope micrographs showed that DMF/tetrahydrofuran and DMF/EtOH ratio and RH value could considerably affect the diameter, surface, and interior morphology of the resultant nanofibers. The nanofiber morphology was dependent upon the polymer/solvent(s)/water ternary phase diagram behavior. In overall, the partial hydrophilicity of styrene/acrylonitrile copolymer resulted in electrospun nanofibers with wrinkled surface. In addition, the incorporation of nonsolvent in the spinning solution and using high RH atmosphere forced the polymeric solution jet to intensively phase separate and, therefore, produce the nanofibers with highly interior porous structure during drying process. The maximal capacity and rate of oil sorption (170 g/g) was observed for the nanofibrous mat prepared using EtOH/DMF (2/3: vol/vol) and RH value of 60% showing the highest internal porosity. The results showed that the oil sorption capability and mechanical strength of the fibrous mat are strongly dependent on nanofibers diameter and porous structure, which can be controlled through adjusting the RH and spinning solvent quality. The electrospun mat with highest Young's modulus (7.68 MPa) was prepared using EtOH/DMF (2/3) binary mixture and RH value of 45%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45586.     

Facile fabrication of superhydrophobic polyimide/polytetrafluoroethylene composite coatings with high water adhesion

A facile casting method was used to fabricate superhydrophobic polyimide/polytetrafluoroethylene composite coatings with high water adhesion. The water contact angles of the composite coatings were larger than 150 °, expressing superhydrophobic property. But water droplets pinned tightly on the composite coating, even if it was upside down. The X‐ray photoelectron spectrum analysis indicated that polyimide and polytetrafluoroethylene coexisted in the resulting coating. The observation with scanning electron microscopy showed that the composite coating formed lotus‐like structure with many spherical polyimide papillae randomly bonding on the surface. But the tops of the polyimide papillae were not covered by lance‐shaped Teflon fibres, forming an inhomogenous and discontinuous surface structure. This special surface chemical distribution and lotus‐like structure combined to contribute to the high adhesive superhydrophobicity. This simple method may greatly extend the application range of high adhesive superhydrophobic surfaces in microcontrollable and microfluidic application. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42810.     

Synthesis and properties of a ternary polyacrylate copolymer resin for the absorption of oil spills

A high‐oil‐absorption resin of a ternary copolymer for the absorption of oil spills was successfully prepared by suspension polymerization, and characterizations of the oil‐absorption resin were also examined in this study. The high‐oil‐absorption resin, a ternary copolymerized long‐chain polyacrylate with styrene (St), butyl methacrylate (BMA), and stearyl methacrylate (SMA) as the monomers and synthesized by suspension polymerization, was introduced. The oil‐absorption resin of St/BMA/SMA was characterized by Fourier transform infrared spectrometry. The particle morphology of the resin was observed by scanning electron microscopy. The effects of different polymerization technological parameters, such as the mass ratios of the monomer, the benzoyl peroxide initiator, and the crosslinking agent of divinylbenzene; the sort and concentrations of the dispersing agent of hydroxyl ethyl cellulose, sodium dodecyl benzene sulfonate, and gelatin, and the polymerization temperature, on the oil absorbency of St/BMA/SMA are discussed in detail. The optimum polymerization conditions of the St/BMA/SMA copolymer were obtained as follows: m_St/m_monomer = 50 wt %, m_BMA/m_{soft monomer} = 60 wt %, m_water/m_oil = 3:1, m_DVB/m_monomer = 1.0 wt %, m_BPO/m_monomer = 1.5 wt %, m_HEC/m_monomer = 0.07 wt %, m_SDBS/m_monomer = 0.03 wt %, m_gelatin/m_monomer = 0.14 wt % (where m is the mass), temperature = 85°C. With increasing content of these factors, the oil absorbency increased at first and then decreased. Compared with binary copolymer St/BMA prepared in previous research, the highest oil absorbencies to dichloromethane were 12.80 and 23.00 g/g in the St/BMA and St/BMA/SMA copolymers, respectively. St/BMA/SMA had a higher oil absorbency and faster oil‐adsorbing rate than St/BMA. The oil absorption in the oil–water mixture and the recovery of the resin were also studied in detail. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40180.     

Enhancing the permeability of reverse osmosis membrane by embedding the star-like rigid supports in the substrate

Thin film composite (TFC) reverse osmosis (RO) membranes with high permeability have been prepared by interfacial polymerization based on tailoring the polysulfone (PSf) substrate structure by in situ embedded poly(p-phenylene terephthamide) (PPTA) star-like rigid supports. The star-like rigid supports were observed by the polarizing optical microscopy (POM) and transmission electron microscope (TEM). The surface properties of the substrates were investigated by FTIR, the water contact angle (WCA), FESEM and AFM. The WCA was decreased from 88.5° to 72.3° with the PPTA increasing from 0% to 8%, and the surface roughness increased from 24.2, 25.1, 33.5 and 58.6 nm, respectively. Furthermore, numerous interconnect micro-structures were constructed in the substrate when the PPTA content was up to 8%. The pure water flux of 8% PPTA/92%PSf substrate was up to 377.0 L m⁻² h⁻¹ and the flux decline rate was lowest (64%) after compacted at 5.5 MPa for 30 min. Otherwise, increasing the PPTA contents in the substrate enhanced the roughness, encouraged nanosheet formation and improved the permeability of TFC RO membranes. The pure water flux of the TFC RO membranes increased from 36.32 to 58.42 L m⁻² h⁻¹, where the NaCl rejection was about 99.5% at 5.5 MPa.     

Fabrication of large‐scale superhydrophobic composite films with enhanced tensile properties by multinozzle conveyor belt electrospinning

Large‐scale superhydrophobic composite films with enhanced tensile properties were prepared by multinozzle conveyor belt electrospinning. First, a strategy of conveyor belt electrospinning was introduced for large‐scale fabrication since the conveyor belt can expand the electrospinning area unlimitedly. During the electrospinning (or electrospraying) process, certain kinds of fibers are combined on the conveyor belt in one electrospinning (or electrospraying) step. The superhydrophobicity of electrospun film can be achieved by the presence of PS beads and bead‐on‐string PVDF fibers, while submicron PAN fibers are responsible for the improvement of mechanical properties. The result shows that CA value of the surface comprising of PS beads and bead‐on‐string PVDF fibers could reach up to 155.0°. As the submicron PAN fibers increased, the value of CA decreased, changing from 155.0° to 140.0°, meanwhile the tensile strength of composite film was enhanced from 1.14 to 4.12 MPa correspondingly which is beneficial to putting the films into practice. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39735.     

Hierarchical superhydrophobic surfaces for oil–water separation via a gradient of ammonia content controlling of dopamine oxidative self-polymerization

Superhydrophobic three-dimensional porous materials have been considering as one of the most promising candidate absorbents for removal and collection of oil spills or organic contaminants from water. In this work, we report a novel and straightforward method for construction of hierarchical superhydrophobic surfaces on the commercial melamine sponge by controlling of the dopamine oxidative selfpolymerization via a gradient of ammonia content. The surface roughness of the sponge was enhanced by the deposited polydopamine coatings whose surfaces exhibited different morphologies at solutions of varied ethanol-ammonia ratios. Thereafter the low-surface free energy moieties were decorated on the surfaces by utilizing a secondary modification platform of polydopamine. Correspondingly, the obtained superhydrophobic melamine sponge achieved a water contact angle of 162.6° ± 1. Furthermore, the superhydrophobic sponge exhibited excellent absorption performances and extraordinary recyclabilities toward a variety of oils and organic solvents. These findings presented in this study offer an effective and versatile approach for oil spills and organic solvents containment removal and environmental remediation in more fundamental and practical fields. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48044.     

Synthesis and properties of ultralow dielectric constant porous polyimide films containing trifluoromethyl groups

In this research, a series of porous copolyimide (co‐PI) films containing trifluoromethyl group (CF₃) were facilely prepared via a phase separation process. The co‐PI were synthesized by the reaction of benzophenone‐3,3′,4,4′‐tetracarboxylic dianhydride (BTDA) with two diamines of 4,4′‐diaminodiphenyl ether (ODA) and 3‐trifluoromethyl‐4,4'‐diaminodiphenyl ether (FODA) with various molar ratios. The flexible and tough porous co‐PI films with about 300 μm thickness and 8～10 μm average diameter could be obtained by solution casting conveniently. The thermal properties of the obtained porous co‐PI films were excellent with a glass transition temperature at 270 °C ～ 280 °C and only 5% weight loss in temperature from 530 °C to 560 °C under nitrogen atmosphere. In addition, the dielectric and hydrophobic properties of porous co‐PI films were remarkably improved owing to the presence of trifluoromethyl groups (CF₃) in the polymer chains. Moreover, our synthesized porous co‐PI films also showed good mechanical properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44494.